Currently Linux PPC is not a supported platform for NetBeans IDE Installer (only x86 and x86_64).
Unfortunately there are no real plans to add Linux PPC support in the nearest future.
As the workaround you can use NetBeans from zip distribution or from Ubuntu packages (if you have ubuntu).

Thanks for your quick reply.
I found the "correct" version to download a few minutes after reporting this bug. It seems it is working well, but the
import settings from 5.0.
What do I "misses" using the platform independent version? I see a major difference compared to x86 version: I cannot
use the system (gnome) look and feel. Is this related to the "independent version" or to the IBM java VM?
Thanks again,
Giuseppe

Giuseppe,
> I found the "correct" version to download a few minutes after reporting this bug. It seems it is working well, but the
> import settings from 5.0.
you mean that you were not offered to import settings from NetBeans 5.0? do you use default userdirs?
> What do I "misses" using the platform independent version?
Actually there are no runtimes in platform independent version like GlassFish, Tomcat, OpenESB (related to SOA
functionality) and WTK (Java ME emulator).
> I see a major difference compared to x86 version: I cannot use the system (gnome) look and feel. Is this related to
the "independent version" or to the IBM java VM?
I do think that it is related to IBM Java VM. There is a number of known issues with using NetBeans on IBM`s Java (both
Java5 and Java6). Unfortunately I don`t know the exact number of those issue or even the overall summary.
Giuseppe, feel free to file any issues and difficulties, that you experience while using NetBeans 6 on IBM`s Java
against 'ide' component, 'code' subcomponent.
Reopening for future tracking... hopefully one day we`ll have Linux/PowerPC support as well.
(See also Issue 127851 that is related to Linux/PPC support in NetBeans C++ modules)

I opened a different report for the problem related to "import settings" panel
http://www.netbeans.org/issues/show_bug.cgi?id=127830
and a second report (exception?) related to an exception I always get when netbeans starts up.
This second report has been automatically sent via netbeans but I cannot find it on netbeans.org. The problems is that I
always get this exception:
INFO [org.netbeans.core.ui.warmup.DiagnosticTask]
java.lang.NoSuchMethodException: com.ibm.lang.management.OperatingSystemMXBeanImpl.getTotalPhysicalMemorySize()
at java.lang.Class.throwNoSuchMethodException(Class.java:280)
at java.lang.Class.getMethod(Class.java:805)
[catch] at org.netbeans.core.ui.warmup.DiagnosticTask.logEnv(DiagnosticTask.java:82)
at org.netbeans.core.ui.warmup.DiagnosticTask.run(DiagnosticTask.java:74)
at org.netbeans.core.WarmUpSupport.run(WarmUpSupport.java:100)
at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:561)
at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:986)

Giuseppe,
I guess that this NoSuchMethodException should be reported against core/ui.
Please attach full messages.log in that issue (if you file it :))
Please add the following info there:
Does it reproducible with fresh userdir (delete ~/.netbeans/6.0) ?
Does it reproducible with development builds of NetBeans (http://bits.netbeans.org/download/trunk/nightly/latest)?